July 25, 1999 - Allies of Chavez win 122 of 128 seats in constitutional assembly, allowing them to draft document tailored to his wishes.

Dec. 15, 1999 - Venezuelans vote to accept Chavez-backed constitution. It eliminates Senate, changes country's name to Bolivarian Republic of Venezuela, and lengthens presidential term from five years to six, clearing the way for Chavez to stay in office as long as 13 years.

July 30, 2000 - In presidential election, Chavez elected to six-year term.

April 13, 2002 - Tens of thousands of Chavez supporters take to streets demanding his return.

April 14, 2002 - Loyal army officers rescue Chavez, restore him to power.

Dec. 3, 2002 - Business organizations, labor unions, political parties and executives from state-run oil company call strike demanding that Chavez agree to nonbinding referendum on his rule. Strike fizzles after two months, government regains control of oil industry.

April 7, 2003 - Chavez fires seven top executives at state oil company for joining strike. Within weeks, 18,000 employees are fired for participating in the strike.

May 28, 2007 - Radio Caracas Television, country's oldest private network, goes off air after Chavez refuses to renew its broadcasting license.

Oct. 14, 2007 - Ailing Fidel Castro calls Chavez's radio show, making his first live appearance on Cuban airwaves since falling ill 14 months earlier, in example of how close the two men have become.

Dec. 2, 2007 - Voters reject amendments proposed by Chavez to make more sweeping changes to constitution, a setback for his drive to transform Venezuela into socialist state.

Sept. 12, 2008 - Orders US ambassador to leave Venezuela, accusing him of conspiring against government. Patrick Duddy later returns to finish his assignment, but Venezuelan and US officials fail to agree on replacement.

Nov. 23, 2008 - Chavez's party wins 17 of 24 gubernatorial races, while opposition candidates triumph in Venezuela's most populous states and cities.

Feb. 15, 2009 - Chavez wins voter approval to eliminate term limits, allowing him to run for re-election indefinitely; he vows to remain in power for at least another decade.

June 10, 2011 - Chavez undergoes surgery in Cuba for pelvic abscess.

June 12, 2011 - Telephones state television in Venezuela from Cuba, saying he is recovering from surgery, but his silence and seclusion following call prompts speculation he could be suffering severe illness.

June 28, 2011 - New videos and photos of Chavez appear on Venezuelan state television, showing him on his feet and talking with Fidel Castro.

June 30, 2011 - Chavez appears on television to confirm he had a cancerous tumour removed. He later says tumour extracted was the size of baseball.

July 4, 2011 - Returns to Venezuela, but later travels to Cuba periodically for chemotherapy and medical tests.

Sept. 23, 2011 - Says he has completed chemotherapy and calls the treatment successful. Says subsequently that tests show no reappearance of cancerous cells.

Feb. 21, 2012 - Says his doctors found new lesion in same place where tumor was previously removed, and announces plans to return to Cuba for surgery.

Feb. 26, 2012 - Undergoes operation that removes tumor from same location in pelvic region. Says later that follow-up tests showed tumor was "recurrence of the initially diagnosed cancer."

March 24, 2012 - Travels to Cuba to begin first round of radiation therapy.

July 9, 2012 - Says at a news conference that tests have shown he is "totally free" of cancer.

Dec. 9, 2012 - Announces that his cancer has returned and that he needs surgery again. Also says for the first time that if he is unable to stay on as president, Vice President Nicolas Maduro should take his place and should be elected president.